In recent years, there has been an increasing demand for miniature multifunction antennas in both military and commercial applications. There has also been a demand for antennas and other radio frequency (RF) systems that can adapt to changing operational frequency band requirements. While software defined radio (SDR) technologies provide the desired flexibility in the receiver and processing systems, antennas are still largely designed as static devices. As a result, many RF systems include multiple antennas to service different applications or physically large antennas to provide a bandwidth wide enough to cover multiple applications with a single antenna. Both of these solutions require that a relatively large area be provided for antennas. As such, these solutions may not be adequate for use in many systems having limited available space (e.g., handheld devices, unmanned vehicles (aerial, terrestrial, and aquatic), body worn sensors, communication satellites, micro-satellites, avionics systems, wireless access points, wireless network interface devices, cellular base stations, and/or others). In addition, if a desired operating frequency band or other operational parameter later changes, these solutions may require an antenna re-design. As will be appreciated, such redesign efforts are both costly and time consuming.
There is a need for wideband, multi-function antenna structures and techniques that are capable of implementation in a relatively compact area. There is also a need for antenna structures and techniques that are capable of adapting to changing operational requirements.